The government like people getting all worked up about sportsball. Even to the point of violence and destruction. It provides the proles with a type of cathartic release that releases any anger they may have building against real injustices against them. Most of the time just watching sportsball is enough, to vicariously participate in mock war. A society under tension may see the mock warfare spill out into minor violence between the "sides" or undirected property damage. Panem et circenses. It's worked for millennia.